• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2441-2443
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• 2004

This paper presents a method that a mobile robot finds location of doors in complex environments and safely traverses the door. A robot must be able to find the door in order that it achieves the behavior that is scheduled after traversing a door. PCA(Principle Component Analysis) algorithm using the vision is used for a robot to find the positions of door. Fuzzy controller using sonar data is used for a robot to avoid a obstacle and traverse the doors.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.10a
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• pp.159-165
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• 1998

In this paper the sway-control problem of a container crane is investigated. The control loop is divided into two stages. The first stage is a modified time optimal control for trolley traversing. The velocity command for trolley traversing consists of three components ; a reference velocity and two feedback signals for compensating the deviations of trolley and sway angle from their desired trajectories. For trolley's exact positioning the trolley dynamics is identified via an error equation identifier structure. The second stage is a nonlinear residual sway control that starts at the end of first stage. The control design for the second stage is investigated from the perspective of controling an underactuated system, and the control law combines the feedback linearization and variable structure control.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.124-129
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• 2004

Recently, the demand for the optical cable is rapidly growing because the number of internee user increases and high speed internet data transmission is required. But the present optical cable winding systems has some serious problems such as pile-up and collapse of cable usually near the flange of the bobbin in the process of the cable winding. To reduce the pile-up collapse in a cable winding systems, a new guiding system is developed for a high-speed self-align cable winding. First of all, the winding mechanism was analyzed and synchronization logics for the motions of winding, traversing, and the guiding were created. A prototype cable winding systems was manufactured to validate the new guiding system and the suggested logic. Experiment results showed that the winding system with the developed guiding system outperformed the system without the guiding system in reducing pile-up and collapse in the high-speed winding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2023-2030
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• 2010

In this paper, we present research results of developing high performance scan conversion unit and implementing it on FPGA chip. To increase performance of scan conversion unit, we propose an architecture of scan converter that is a SIMD architecture and uses tile-based traversing method. The proposed scan conversion unit can operate about 124Mhz clock frequency on Xilinx Vertex4 LX100 device. To verify the scan conversion unit, we also develop shader unit, texture mapping unit and $240{\times}320$ color TFT-LCD controller to display outputs of the scan conversion unit on TFT-LCD. Because the scan conversion unit implemented on FPGA has 311Mpixels/sec pixel rate, it is applicable to desktop pc's 3d graphics system as well as mobile 3d graphics system needing high pixel rates.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.4 s.7
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• pp.97-116
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• 2002

In this papers, a finite element formulation is proposed for dynamic analysis of vehicle-bridge interaction problems under realistic loading conditions. Although the formulation presented in this paper is based on the consideration of only a single traversing vehicle, it can be extended to include several different bridge configurations. The traversing vehicle and the vibrating bridge superstructure are considered as an integrated system. Hence, although material and geometric nonlinearities are excluded, this introduces nonlinearity into the problem. Various vehicle models, including those with suspension systems, are considered. Traveling speed of the vehicle can be varied. The finite element discretization of the bridge structure permits the inclusion of arbitrary geometrical configurations, and surface and boundary conditions. To obtain accurate solutions, time integration of the equation of vehicle-bridge motion is carried out by using the Newmark method in connection with a predictor-corrector algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.125-128
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• 2003

In machine tool design, fast traversing cannot be achieved without reducing mass of the moving part. Honeycomb sandwich panel is extremely lightweight, and relatively rigid at the same time. We can reduce much weight when we selectively utilize honeycomb sandwich panels as stiffeners on machine tool structures. Feasibility of reducing weight is studied using a beam structure with both ends fixed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.3
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• pp.436-444
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• 1997

Three-dimensional conjugate heat transfer and particle deposition on a circular cylinder in the OVD process are numerically investigated. Flow and temperature fields are obtained by an iterative method, and thermophoretic particle deposition is simulated. Effects of the heat conduction in the cylinder, the rotation speed of the cylinder, and the traversing speed of torch on the deposition are studied. Effects of variable properties are also included. As the conductivity of the cylinder decreases, particle deposition rate and deposition efficiency greatly decrease due to the reduced temperature gradient. The rotation of the cylinder has no significant effect on the deposition due to the small diameter of the cylinder and low speed of rotation. Since the increase of the torch speed keeps the surface low temperature, the particle deposition increases with the traversing speed.

• International Journal of Safety
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• v.5 no.1
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• pp.1-4
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• 2006

The safety performance of the current collection system is evaluated by conducting a test run in which accelerometer and load cell signals are analyzed. It has been found that the current collection performance is strongly influenced by the train speed, with the major frequency components arising from the train traversing the span spacing and the 8.5 Hz component originating from the panhead resonance. The train acceleration is found to have significant influence on the span passing frequency but negligible effect on the resonant response.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.478-482
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• 2002

Recently, the demand for the optical cable is rapidly glowing because the number of internet user increases and high speed internet data transmission is required. To meet this demand, it is necessary to have a sufficient manufacturing capability for mass and high-quality production. But the present optical cable winding system has some serious problems such that the optical cable of radius (6 mm -40 mm) is often piled up and collapsed usually at the edge of the bobbin in the process of the cable winding. It is often necessary to have an additional operator in order to adjust the cable, which causes the productivity decrease. In order to improve a performance of cable winding system which deals with relatively thick cable( radius : 6 mm -40 mm ), we developed a new guiding system for a high-speed self-align cable winding. First of all, the winding mechanism was analyzed. Synchronization logics for the motions of winding, traversing, and the guiding were created and implemented by using the PLC and guiding system controller in a prototype cable winding system manufactured in the CILS( Computer Integrated Large scale System ) lab. An experimental verification was carried out to validate the logic. Results showed that the winding system with the developed guiding system outperformed in reducing pile-up and collapse in the high-speed winding(up to 300 mm/s) compared with the system without the guiding system.

• Journal of Biosystems Engineering
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• v.30 no.6 s.113
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• pp.366-372
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• 2005

The objective of this study was to evaluate the bump crossing and loading stability of a proto-type mini-forwarder under development. The evaluation was performed by computer simulation using a multi-body dynamic analysis program, Recur- Dyn 5.21. The proto-type was modeled and its properties such as mass, mass center, and mass moment of inertia were determined using 3D CAD modeler, Solid Edge 8.0. The $\%$ errors of masses, mass center, mass moment of inertia, and vertical motion of the model were within less than $10\%$ and the model's behavior agreed relatively well with those of the proto-type when traversing over a rectangular bump. Using the validated model, bump crossing of the proto-type was simulated and the loading limit was determined. It was found that effects of the shapes of bump on the bump crossing performance was insignificant within the practical heights of bumps. Stability of bump crossing increased with loading. However, loading of longer logs than 2.7 m made the crossing unstable because the ends of logs contacted ground when traversing over the bump. The maximum loading capacity of the proto-type was estimated to be 7.8 kN of 2.7 m long logs.